Transcript Shielded Metal Arc Welding - Central Columbia School District

Shielded Metal Arc
Welding
Arc Welding?
•Uses
electricity
for heat
Arc Welding ?
•Electrodes
(Rods)
covered
with flux
Arc Welding?
•Gas cloud
(Shield)
around the
metal during
welding
Arc Welding
•Heat for arc
welding comes
from electricity
Arc Welding
•Welder = machine
used for welding
that produces a
current
Arc Welding
•Arc = discharge of
electricity
•Weldor = a person
who welds
Arc Welding
•Electrodes = flux
coated metal rods
Arc Welding
•Electrode Holder =
spring loaded device
with insulated
handles used to grip
the electrode
Arc Welding
•Ground Clamp =
spring loaded clamp
that is attached to
an electrical cable
Arc Welding
•Chipping Hammer
= steel hammer with
a sharp edge/point
and a wire brush
Arc Welding
•Helmets = cover
your head and neck
region-- a # 10
shield is required
Arc Welding
•Safety Glasses =
must be worn under
the welding helmet
Arc Welding
•Welding Gloves =
insulated gloves worn
to protect hands from
heat and sparks (not
100%)
Welding Process
W=VXA
W = Watts = measure
of energy available
W=VXA
V = Voltage =
measure of electrical
pressure
W=VXA
A = Amp = rate of
flow of current
Temperature
•Arc can be up to
9000 degrees F.
Temperature
• Depends on:
–Arc Length
–Electrode type
–Amp Setting
–Base Metal
Duty Cycle
•The percentage of
time that a welder
can operate without
overheating
Duty Cycle
•The number of
minutes out of 60
that a welder can
operate at full
capacity
AC/DC
•AC
–Alternating
Current
–Rev. Direction
AC/DC
•AC
-U.S. 60 Cycles per
second
AC/DC
•AC
–Use Transformers
to step-down
voltage and
increase amps
AC/DC
•DC
–Direct Current
–Electricity flows
in one direction
AC/DC
•DC
–Straight vs.
Reverse Polarity
–Use Generators to
produce the DC
Electrode Coding
NEMA
•Uses color coding on
the rods
• 3 areas on the rod
Electrode Coding
AWS
•# coding system on
the rods
•Each # stands for
something
E6013
•1
=
•E =
Welding
Electrode
Position
•60 =
•3
=
Tensile
Welding
Strength
Current
Flux
•Shields
Outside
gasses
Flux
•Combines
with
metal
impurities
Flux
•Forms Slag
•Makes and
Maintains
Arc
What Affects a
Weld Bead???
•Temp of Base Metal
–Adjust your Amps
What Affects a
Weld Bead???
•Electrode Diameter
and Flux Type
What Affects a
Weld Bead???
•Amps
–Select according
to the thickness of
your metal
What Affects a
Weld Bead???
•Arc Length
–“Frying Bacon”
What Affects a
Weld Bead???
•Electrode Angle
–10 to 15 degrees
from vertical
What Affects a
Weld Bead???
•Speed of Travel
–Even across the
metal
Arc Welding Safety
•Weld on a
proper surface
•Fire
Exting./blanket
nearby
Arc Welding Safety
•Surrounding
area???
•Wear all safety
equipment/gear